Public water system · TX0790489
ActiveSienna MUD 4
At a glance
Sienna MUD 4 (PWSID TX0790489) is an active community water system in Fort Bend County, Texas. It reports serving 6,435 people through 2,145 service connections. Its primary water source is purchased groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in November 2025.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
6,435
Service connections
2,145
Primary source
GWP
Purchased groundwater
System type
CWS
Community water system
System record
How does Sienna MUD 4 compare with other water systems in Fort Bend County?
By EPA's size categories, Sienna MUD 4 is a medium system (3,301 to 10,000 people). Fort Bend County has 287 active public water systems. Its population served is about twice the county average of 3,155 people per system, and accounts for 0.7% of the 905,329 people reported by systems filed under the county. Across Texas, the 7,078 active systems average 4,789 people each. Nationally, the average active community water system reports serving 6,703 people, so Sienna MUD 4 is roughly in line with that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Texas has 4,594 active community water systems, 65% of the state's 7,078 active systems. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own. 302 Texas systems (4.3%) list purchased groundwater as their primary source.
Who owns and regulates Sienna MUD 4?
EPA lists Sienna MUD 4 as owned by a local government. The TX state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 157 of the 287 active systems in Fort Bend County (55%) are also owned by a local government.
Does Sienna MUD 4 have drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in November 2025. The violations listed here began between October 2012 and November 2025. By type: 7 monitoring and reporting, 4 public notice, recordkeeping or other and 1 monitoring. The contaminant or rule involved most often is Lead and Copper Rule (5 of them). EPA lists 12 as resolved. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2025-11-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2015-09-29 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2015-04-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2014-07-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2014-01-01 | Monitoring and reportingInitial Tap Sampling for Pb and Cu · code 51 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2013-09-29 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2013-03-12 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2013-02-10 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2013-01-10 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2012-11-10 | Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75 | Public Noticecode 7500 | No | Resolved |
| 2012-11-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 2012-10-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
Sienna MUD 4: frequently asked questions
Who runs Sienna MUD 4?
Sienna MUD 4 (PWSID TX0790489) is a community water system owned by a local government. It is regulated by the TX state drinking water program.
How many people does Sienna MUD 4 serve?
Sienna MUD 4 reports serving 6,435 people through 2,145 service connections in Fort Bend County, Texas.
Where does Sienna MUD 4 get its water?
EPA SDWIS lists this system's primary water source as purchased groundwater. Purchased groundwater means the system buys groundwater from another public water system rather than drawing its own.
Does Sienna MUD 4 have any drinking water violations?
Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in November 2025. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is Sienna MUD 4's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, none is health-based, and the most recent began in November 2025. For current results, consult the system's annual water quality report, EPA ECHO, or the TX state drinking water program.
Where can I find Sienna MUD 4's water quality report?
As a community water system, Sienna MUD 4 must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Fort Bend County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| City of Sugar Land | Fort Bend | 90,909 | Community | Surface water |
| Fort Bend County Wcid 2 | Fort Bend | 49,173 | Community | Surface water |
| City of Rosenberg | Fort Bend | 43,158 | Community | Purchased surface water |
| City of Fulshear | Fort Bend | 34,000 | Community | Groundwater |
| City of Richmond | Fort Bend | 25,326 | Community | Surface water |
| Fort Bend County MUD 30 | Fort Bend | 16,794 | Community | Purchased surface water |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Sienna MUD 4, PWSID TX0790489, Texas”, https://aquacensus.com/water-systems/texas/sienna-mud-4-tx0790489 (data as of October 1, 2026).